-- binary
04 0f # version, type
00 70 # length
12 34 56 78 # xid
00 01 # command
03 # group_type
00 # pad
00 00 00 05 # group_id
00 30 # buckets[0].len
00 01 # buckets[0].weight
00 00 00 05 # buckets[0].watch_port
ff ff ff ff # buckets[0].watch_group
00 00 00 00 # pad
00 00 # buckets[0].actions[0].type
00 10 # buckets[0].actions[0].len
00 00 00 05 # buckets[0].actions[0].port
00 00 # buckets[0].actions[0].max_len
00 00 00 00 00 00 # pad
00 00 # buckets[0].actions[1].type
00 10 # buckets[0].actions[1].len
00 00 00 06 # buckets[0].actions[1].port
00 00 # buckets[0].actions[1].max_len
00 00 00 00 00 00 # pad
00 30 # buckets[1].len
00 01 # buckets[1].weight
00 00 00 06 # buckets[1].watch_port
ff ff ff ff # buckets[1].watch_group
00 00 00 00 # pad
00 00 # buckets[1].actions[0].type
00 10 # buckets[1].actions[0].len
00 00 00 05 # buckets[1].actions[0].port
00 00 # buckets[1].actions[0].max_len
00 00 00 00 00 00 # pad
00 00 # buckets[1].actions[1].type
00 10 # buckets[1].actions[1].len
00 00 00 06 # buckets[1].actions[1].port
00 00 # buckets[1].actions[1].max_len
00 00 00 00 00 00 # pad
-- python
ofp.message.group_mod(
    xid=0x12345678,
    command=ofp.OFPGC_MODIFY,
    group_type=ofp.OFPGT_FF,
    group_id=5,
    buckets=[
        ofp.bucket(
            weight=1,
            watch_port=5,
            watch_group=0xffffffff,
            actions=[
                ofp.action.output(port=5, max_len=0),
                ofp.action.output(port=6, max_len=0)]),
        ofp.bucket(
            weight=1,
            watch_port=6,
            watch_group=0xffffffff,
            actions=[
                ofp.action.output(port=5, max_len=0),
                ofp.action.output(port=6, max_len=0)])])